This invention relates to a fluid coupling assembly and, more particularly, to a fluid coupling assembly which utilizes a stationary housing, a gear pump, an electronic actuator and a rotor design with internal fluid passages to achieve improved performance, speed control and cooling characteristics.
Fluid coupling assemblies utilize fluid flow forces to selectively transfer torque and power between rotating devices. Fluid coupling assemblies typically include a housing having an interior chamber containing an amount of fluid, and a rotor or drive member which selectively rotates within the interior chamber. The fluid acts in shear with the rotating drive member to transmit torque to the housing, thereby transferring torque between the drive member and housing.
Fluid couplings are widely used in automotive applications to selectively engage and disengage rotating devices, such as an engine cooling fan or other device, as well as to limit the maximum rotational speed of the fan or device. One drawback of such fluid couplings is that they are extremely sensitive to the amount of fluid or oil that is contained within the housing and that is used to transfer torque from the rotor to the housing. Due to this high sensitivity, if even a very small amount of fluid escapes from the housing, the fluid coupling will malfunction or become inoperable. Furthermore, the fluid flow or circulation within these prior fluid couplings is relatively low and causes these fluid couplings to operate at relatively high temperatures. As a result, these prior fluid couplings must be manufactured from relatively expensive heat conductive material, such as die cast aluminum, thereby undesirably increasing manufacturing cost and complexity. Moreover, the speed control response of these prior fluid couplings is relatively slow due to the relatively low oil flow within the fluid coupling.
There is therefore, a need for a new and improved fluid coupling assembly which overcomes the previously delineated drawbacks of these prior fluid coupling assemblies.
It is a first object of the invention to provide a fluid coupling assembly which overcomes at least some of the previously delineated drawbacks of prior fluid coupling assemblies.
It is a second object of the invention to provide a fluid coupling assembly which utilizes an internal gear pump or other fluid flow device to achieve a relatively high volume of oil flow within the device, thereby allowing the device to be cooled relatively easily and quickly.
It is a third object of the invention to provide a fluid coupling assembly which utilizes a stationary housing having a water jacket to provide cooling to the assembly.
It is a fourth object of the invention to provide a fluid coupling assembly which is adapted for use with an automotive fan assembly or other device and which utilizes a hollow rotor design with internal fluid passages to achieve improved speed control performance relative to prior fluid couplings.
It is a fifth object of the invention to provide a fluid coupling assembly which is relatively insensitive to the amount of fluid or oil within the assembly and which includes a removable plug or member which allows the assembly to be selectively refilled.
According to a first aspect of the present invention, a fluid coupling assembly is provided and includes a stationary housing which forms a first chamber containing an amount of fluid; a rotatable housing which is disposed within the first chamber and which forms a second chamber which is in fluid communication with the first chamber; a rotor which is disposed within the second chamber and which is selectively rotatable within the second chamber; and a pump assembly which is effective to communicate the amount of fluid from the first chamber to the second chamber, thereby causing the amount of fluid to transmit torque from the rotating rotor to the rotatable housing.
According to a second aspect of the present invention, a fluid coupling assembly is provided and includes a stationary housing which forms a first chamber; a rotatable housing which is disposed within the first chamber and which forms a second chamber; a hollow rotor which is rotatably disposed within the second chamber and which includes a channel which is selectively and fluidly coupled to the first chamber and the second chamber; an amount of fluid which is contained within the first and second chambers and the channel, and which is effective to selectively transfer torque from the hollow rotor to the rotatable housing; and a selectively actuatable valve assembly which is effective to control the amount of fluid which is communicated from the first chamber to the channel and the second chamber, thereby controlling the amount of fluid within the second chamber and the torque transmitted from the rotor to the rotatable housing.
These and other features, aspects and advantages of the invention will become apparent by reading the following specification and by reference to the following drawings.